Rock-breaking tool

ABSTRACT

An elongated rock-breaking bar is provided at one end with a chisel point and at the opposite end with a chisel edge. Intermediate these ends are a pair of longitudinally spaced collars between which a hammer member is mounted slidably on the bar. In one embodiment the bar is made in two detachable longitudinal sections and the hammer member is made in one piece. In another embodiment the bar is made in one piece and the hammer member is made in two detachable lateral sections.

United States Patent 535,387 3/1895 Miller 30/277 716,274 12/1902 Peirce 173/91X 532,008 l/1895 Neu 145/30.5

, 1,903,548 4/1933 Kreis 145/61.4UX FOREIGN PATENTS 848,786 9/1 952 Germany 173/91 Primary Examiner- Harold D. Whitehead Attorney-Oliver D. Olson ABSTRACT: An elongated rock-breaking bar is provided at one end with a chisel point and at the opposite end with a chisel edge. Intermediate these ends are a pair of longitudinally spaced collars between which a hammer member is mounted slidably on the bar. In one embodiment the bar is made in two detachable longitudinal sections and the hammer member is made in one piece. In another embodiment the bar is made in one'piece and the hammer member is made in two detachable lateral sections.

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' ROCK-BREAKING TOOL BACKGROUND OF THE INVENTION This invention relates to rock-breaking tools of the type used by professional geologists and amateur rock bounds, and more particularly to an integrated tool which performs the functions of a rock chisel and sledge.

Heretofore the separation of rock specimens from earth deposits and the reduction of such specimens to more usable sizes has been accomplished by use either of a conventional geologist pick, for small specimens, or of a rock chisel and sledge, for larger specimens. The primary disadvantage attending the use of the pick is the difficulty repeatedly to strike the same spot at the same angle, resulting in improper fragmentation of the specimen and the consequent production of undesirable chips and grindings. The primary disadvantage attending the use of a rock chisel and sledge resides in the inherent hazard of bodily injury when the sledge misses or ricochets from the chisel.

A further disadvantage attending the use of either prior forms of tools resides in the severe limitation of utility in close quarters.

SUMMARY OF THE INVENTION I In its basic concept the present invention provides an elongated chisel bar, an integral sliding hammer member operable between a pair of spaced abutments on the bar for driving the associated end of the bar into rock.

It is by virtue of the foregoing basic concept that the primary objective of the present invention is achieved, namely to overcome the disadvantages of prior tools as enumerated hereinbefore.

Another important object of this invention is the provision of a rock-breaking tool of simplified and rugged construction for economical manufacture and for heavy duty, and which enables the breaking of rock with speed and precision.

The foregoing and other objects and advantages of this invention will appear from the following detailed description, taken in connection with the accompanying drawing of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view of a rock-breaking tool embodying the features of the present invention.

EEG. 2 is a sectional view taken on the line 2-3 in FIG. 1.

PEG. 3 is a fragmentary sectional view taken on the line 3-3 in FIG. ll. FIG. 4 is a plan view of a modified form of hammer member.

FIG. 5 is a sectional view taken on the line 5-5 in FIG. 4.

FIG. 6 is a sectional view taken on the line 6-6 in FIG. 4-.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment illustrated in FIGS. 1-3, the tool includes an elongated steel bar in the form of two longitudinal sections M9 and 12. These sections are joined together detachably by such means as the releasable interengagement of the externally threaded, reduced'end portion 14 of the bar section iii and the internally threaded bore 16 in the adjacent end of the other bar section 12.

The opposite ends of the bar are provided with rock-breaking contoured chisel tips. Thus, one end is provided with a chisei edge 11%, while the opposite end is provided with a chisel point 20.

The bar is provided with a pair of longitudinally spaced, enlarged shoulders 22, 24 which provide abutments for the adjacent striking ends of a hollow hammer member 26. In the embodiments illustrated in FIGS. ll3, the hammer member is of one-piece construction and is provided with a longitudinal bore 2% which is slightly largerthan the cross section of the bar. The hammer member is installed on the bar by separating the sections and H2 at their threaded connections, inserting one bar section through the bore in the hammer member, and then joining the two bar sections together.

The hammer member is slidable freely on the bar between the enlarged abutments, and it preferably is contoured to provide effective gripping by the hand. Thus, a selected one of the chisel tips may be placed at a desired location on a rock, the bar steadied by one hand and the handle member gripped in the other hand. The handle member is slid along the bar away from the abutment adjacent the operating tip, and then is accelerated rapidly into contact with said abutment member with substantial force. This force is transmitted to the tip to effect breaking of the rock. Repeated striking of the abutment with the hammer member is continued until the desired result is achieved.

The elongated bar may be provided in one piece, rather than in the two longitudinal sections 10 and 12 illustrated. In such event the hammer member illustrated in FIGS. ti-6 also is provided. In this embodiment the hammer member comprises a pair of transverse sections 30 and 32 which are adapted to be secured together to form an integral unit provided with a longitudinal bore. Peripheral segments adjacent the opposite ends of each section are removed to form recesses 34 for receiving the head and nut of securing bolts 36 which extend through aligned openings 38 in the sections.

Each section preferably is provided adjacent one end with a transverse tongue 40 and adjacent the opposite end with a transverse groove 42. The tongue of one section is adapted to be received in the groove of the other section, whereby to align the sections and to relieve the securing bolts of the shock stresses resulting from the hammer member striking the abutments on the bar.

As will be apparent, the handle member is installed upon the elongated bar, between the abutments, by removing the bolts and separating the sections so that the latter may be fitted around the bar.

The securing bolts than are reinstalled and tightened, whereupon the tool is ready for use.

From the foregoing it will be appreciated that the present invention provides a rock-breaking tool of simplified and rugged construction for economical manufacture and heavy duty. Because the selected chisel tip may be positioned accurately on a rock and maintained in that position during operation of the hammer member, precise breaking of the rock may be achieved with minimum production of chips and grindings. Further, the tool may be utilized effectively in confined quarters, since minimum space is required for its manipulation.

It will be apparent to those skilled in the art that various changes in the size, shape and arrangement of parts described hereinbefore may be made without departing from the spirit of this invention and the scope of the appended claims.

I claim:

1. A rock-breaking tool comprising:

an elongated bar having rock-breaking contoured tips at its opposite ends;

b. a pair of longitudinally spaced, enlarged abutment members on the bar integral with and intermediate the ends of the latter; and

c. a hollow hammer member mounted slidably on the bar between said abutment members for selective striking engagement with the latter, the hammer member comprismg:

l. a pair of substantially identical lateral halves; and 2. securing means interengaging said halves for releasably securing them together.

2. The tool of claim 1 including interengaging tongue and groove means on the lateral halves of the hammer member for securing them against relative longitudinal displacement.

3. A rock-breaking tool comprising:

a. an elongated bar having rock-breaking contoured tips at its opposite ends, the bar comprising:

1. two longitudinal sections; and

2. interengaging means on the ends of the sections opposite said contoured tips for releasably securing said sections together;

ing a longitudinal bore therethrough mounted slidably on the bar between said abutment members for selective striking engagement with the latter. 

2. securing means Interengaging said halves for releasably securing them together.
 2. The tool of claim 1 including interengaging tongue and groove means on the lateral halves of the hammer member for securing them against relative longitudinal displacement.
 2. interengaging means on the ends of the sections opposite said contoured tips for releasably securing said sections together; b. a pair of longitudinally spaced, enlarged abutment members one on each of the longitudinal bar sections integral with and intermediate the ends of the latter; and c. a hollow hammer member of one-piece construction having a longitudinal bore therethrough mounted slidably on the bar between said abutment members for selective striking engagement with the latter.
 3. A rock-breaking tool comprising: a. an elongated bar having rock-breaking contoured tips at its opposite ends, the bar comprising: 